From 64a00b43e63c916f1bf4f6b7f519db0e198ba9d4 Mon Sep 17 00:00:00 2001 From: Devin Heitmueller Date: Wed, 27 May 2009 23:23:37 -0300 Subject: [PATCH] V4L/DVB (11923): em28xx: Don't let device work unless connected to a high speed USB port The em28xx basically just doesn't work at 12 Mbps. The isoc pipe needs nearly 200 Mbps for analog support, so users would see garbage video, and on the DVB/ATSC side scanning is likely to work but if the user tried to tune it would certainly appear to have failed. It's better to fail explicity up front and tell the user to plug into a USB 2.0 port, than to let the driver load and the user have weird problems with tuning and garbage video. Signed-off-by: Devin Heitmueller Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/em28xx/em28xx-cards.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/drivers/media/video/em28xx/em28xx-cards.c b/drivers/media/video/em28xx/em28xx-cards.c index fe2a471e5f64..72cab9bcdf95 100644 --- a/drivers/media/video/em28xx/em28xx-cards.c +++ b/drivers/media/video/em28xx/em28xx-cards.c @@ -2365,6 +2365,20 @@ static int em28xx_usb_probe(struct usb_interface *interface, ifnum, interface->altsetting->desc.bInterfaceNumber); + /* + * Make sure we have 480 Mbps of bandwidth, otherwise things like + * video stream wouldn't likely work, since 12 Mbps is generally + * not enough even for most Digital TV streams. + */ + if (udev->speed != USB_SPEED_HIGH) { + printk(DRIVER_NAME ": Device initialization failed.\n"); + printk(DRIVER_NAME ": Device must be connected to a high-speed" + " USB 2.0 port.\n"); + em28xx_devused &= ~(1<= EM28XX_MAXBOARDS) { printk(DRIVER_NAME ": Supports only %i em28xx boards.\n", EM28XX_MAXBOARDS); -- 2.34.1